Progress towards a Large Space-Time Area Lattice Atom Interferometer

Matter wave interferometry using a spatial superposition of ultracold atoms is a powerful quantum sensing tool for tests of fundamental physics and inertial sensing. In lattice atom interferometry, the measurement time is increased by levitating atoms in an optical lattice, such as the mode of an optical cavity. Our demonstrations of minute scale spatial coherence in a lattice atom interferometer suggest that dephasing of the thermal atoms in the presence of tilt-noise is the leading cause for loss of coherence. We are constructing a new apparatus that will have enhanced performance by suppressing tilt-noise with active vibration isolation of both the vacuum chamber and cavity mirrors, as well as by reducing temperature through evaporative cooling. Together, these upgrades could enable acceleration sensitivity gains of up to 2-3 orders of magnitude and novel fundamental physics tests using localized source masses. In particular, by integrating a lattice atom interferometer with a diamagnetic, high-Q torsion pendulum, we could generate macroscopic entangled states and ultimately probe the coherence of the gravitational force. We report on the recent progress towards creating interferometry fringes in our apparatus.